Revenue (Schedule of Contract Liability) (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Sep. 30, 2024
Contract With Customer Liability [Line Items]
Current contract liabilities	$ 47,419	$ 56,791
Noncurrent contract liabilities	432,909	424,609
Deferred Revenue from Material Rights from JV Formation [Member]
Contract With Customer Liability [Line Items]
Current contract liabilities	6,939	6,580
Noncurrent contract liabilities	234,069	232,164
Deferred Revenue From Advance Invoicing And/Or Prepayments From Customers [Member]
Contract With Customer Liability [Line Items]
Current contract liabilities	15,749	23,706
Noncurrent contract liabilities	7,542	6,437
Liability Related To Customer Supplied Inventory [Member]
Contract With Customer Liability [Line Items]
Current contract liabilities	16,648	20,563
Deferred Revenue From Material Rights Related To Engineering And Development Funding [Member]
Contract With Customer Liability [Line Items]
Current contract liabilities	8,083	5,942
Noncurrent contract liabilities	$ 191,298	$ 186,008